U.S. patent application number 16/704026 was filed with the patent office on 2020-06-18 for high-voltage generator for providing a high-voltage pulse.
This patent application is currently assigned to Siemens Healthcare GmbH. The applicant listed for this patent is Siemens Healthcare GmbH. Invention is credited to Oliver HEUERMANN, Martin KOSCHMIEDER, Marvin MOELLER, Sven MUELLER, Stefan WILLING.
Application Number | 20200194210 16/704026 |
Document ID | / |
Family ID | 70858737 |
Filed Date | 2020-06-18 |
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United States Patent
Application |
20200194210 |
Kind Code |
A1 |
MOELLER; Marvin ; et
al. |
June 18, 2020 |
HIGH-VOLTAGE GENERATOR FOR PROVIDING A HIGH-VOLTAGE PULSE
Abstract
A high-voltage generator provides a high-voltage pulse including
a plurality of energy storage cells, each including two input and
two output terminals and a capacitor. A controllable switching
element is connected to the input terminals and plus terminals and
minus terminals are electrically connected to one another via a
respective diode. The high-voltage generator further includes a
series connection comprising the energy storage cells, a pulse
transformer, and a charging terminal for charging the capacitors.
In an embodiment, the high-voltage generator is developed so that a
greater pulse rate can be achieved. In an embodiment, at least a
respective one of the energy storage cells includes an electrical
resistance, connected in series with the diode connecting the plus
terminals of the respective energy storage cell.
Inventors: |
MOELLER; Marvin; (Jena,
DE) ; MUELLER; Sven; (Urbich, DE) ;
KOSCHMIEDER; Martin; (Uhlstaedt-Kirchhasel, DE) ;
WILLING; Stefan; (Rudolstadt, DE) ; HEUERMANN;
Oliver; (Adelsdorf, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Healthcare GmbH |
Erlangen |
|
DE |
|
|
Assignee: |
Siemens Healthcare GmbH
Erlangen
DE
|
Family ID: |
70858737 |
Appl. No.: |
16/704026 |
Filed: |
December 5, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03K 3/012 20130101;
H01J 23/34 20130101; H03K 3/53 20130101; H01J 25/50 20130101 |
International
Class: |
H01J 25/50 20060101
H01J025/50; H01J 23/34 20060101 H01J023/34; H03K 3/53 20060101
H03K003/53 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 2018 |
DE |
102018221518.9 |
Claims
1. A high-voltage generator for providing a high-voltage pulse, the
high-voltage generator comprising: a plurality of energy storage
cells, each energy storage cell of the plurality of energy storage
cells, including two input terminals, two output terminals and one
capacitor, the one capacitor being connected with a first terminal
to minus terminals of the two input terminals and being connected
with a second terminal to plus terminals of the two output
terminals, wherein a controllable switching element is connected to
the input terminals, wherein the plus terminals and the minus
terminals are respectively connected electrically via respective
diodes, respective anodes of the diodes being connected to the
input terminals and respective cathodes of the diodes being
connected to the output terminals; a series connection, including
the plurality of energy storage cells, respective input terminals
of a respective one of the plurality of energy storage cells being
connected to respective output terminals of one of the plurality of
energy storage cells arranged relatively upstream in the series
connection, the series connection providing respective input
terminals of a relatively first energy storage cell of the
plurality of energy storage cells as the input terminals and
providing respective output terminals of a relatively last energy
storage cell of the plurality of energy storage cells as the output
terminals; a pulse transformer including at least one primary
winding and including at least one secondary winding, to provide
the high-voltage pulse, the at least one primary winding being
connected to the plus terminals of the series connection; and a
charging terminal to charge capacitors of the plurality of energy
storage cells with energy from an energy source, connectable to the
charging terminal, wherein a minus terminal of the charging
terminal is provided by the minus terminal of the output terminal
of the series connection and a plus terminal of the charging
terminal is provided by one of the plus terminals of the relatively
first energy storage cell of the plurality of energy storage cells,
wherein at least one respective energy storage cell, of the
plurality of energy storage cells, includes an electrical
resistance, connected in series with the diodes connecting the plus
terminals of the at least one respective energy storage cell.
2. The high-voltage generator of claim 1, wherein only the
relatively first energy storage cell of the plurality of energy
storage cells includes the electrical resistance.
3. The high-voltage generator of claim 1, wherein a resistance
switching element is connected in parallel with the electrical
resistance.
4. The high-voltage generator of claim 1, wherein the plus terminal
of the charging terminal is first provided to the plurality of
energy storage cells by the plus terminal of the output
terminal.
5. The high-voltage generator of claim 1, wherein the electrical
resistance includes a resistance value dependent on at least one of
an impedance of the pulse transformer and a capacitance of a
circuit connected to the at least one secondary winding.
6. The high-voltage generator of claim 1, wherein the electrical
resistance is embodied to be adjustable with respect to a
resistance value of the electrical resistance.
7. The high-voltage generator of claim 1, wherein the electrical
resistance includes a resistance value in a range of approx.
0.5.OMEGA. to approx. 15.OMEGA..
8. The high-voltage generator of claim 1, wherein the electrical
resistance is embodied for an electric power in a range of approx.
0.2 kW to approx. 10 kW.
9. The high-voltage generator of claim 1, wherein the electrical
resistance is arranged so as to be exchangeable.
10. The high-voltage generator of claim 1, wherein the electrical
resistance is embodied at least partially as a sheet resistor.
11. A high-frequency generator, comprising: a magnetron; and the
high-voltage generator of claim 1, connected to the magnetron.
12. The high-voltage generator of claim 2, wherein a resistance
switching element is connected in parallel with the electrical
resistance.
13. The high-voltage generator of claim 2, wherein the plus
terminal of the charging terminal is first provided to the
plurality of energy storage cells by the plus terminal of the
output terminal.
14. The high-voltage generator of claim 2, wherein the electrical
resistance includes a resistance value dependent on at least one of
an impedance of the pulse transformer and a capacitance of a
circuit connected to the at least one secondary winding.
15. The high-voltage generator of claim 2, wherein the electrical
resistance is embodied to be adjustable with respect to a
resistance value of the electrical resistance.
16. The high-voltage generator of claim 7, wherein the electrical
resistance includes a resistance value of 5.OMEGA..
17. The high-voltage generator of claim 8, wherein the electrical
resistance is embodied for an electric power of 1 kW.
18. The high-voltage generator of claim 2, wherein the electrical
resistance is arranged so as to be exchangeable.
19. The high-voltage generator of claim 2, wherein the electrical
resistance is embodied at least partially as a sheet resistor.
Description
PRIORITY STATEMENT
[0001] The present application hereby claims priority under 35
U.S.C. .sctn. 119 to German patent application number DE
102018221518.9 filed Dec. 12, 2018, the entire contents of which
are hereby incorporated herein by reference.
FIELD
[0002] Embodiments of the invention generally relate to a
high-voltage generator for providing a high-voltage pulse, having a
plurality of energy storage cells, wherein each of the energy
storage cells has in each case at least two input and two output
terminals as well as a capacitor, which is connected with a first
of its terminals to a minus terminal of the two input terminals and
with a second of its terminals to a plus terminal of the two output
terminals, wherein a controllable switching element is connected to
the input terminals and the plus terminals and the minus terminals
are in each case connected electrically to one another by way of a
diode, by respective anodes of the diodes being connected to the
input terminals and respective cathodes of the diodes being
connected to the output terminals, a series connection comprising
the energy storage cells, in which the respective input terminals
of a respective one of the energy storage cells are connected to
the respective output terminals of one of the energy storage cells
arranged upstream in the series connection, so that as input
terminals the series connection provides the input terminals of the
first of the energy storage cells and as output terminals the
series connection provides the output terminals of the last of the
energy storage cells, a pulse transformer with at least one primary
winding and at least one secondary winding for providing the
high-voltage pulse, wherein the at least one primary winding is
connected to the plus terminals of the series connection, and a
charging terminal for charging the capacitors with energy from an
energy source which can be connected to the charging terminal,
wherein a minus terminal of the charging terminal is provided by
the minus terminal of the output terminal of the series connection
and a plus terminal is provided by one of the plus terminals of the
first of the energy storage cells.
[0003] Furthermore, embodiments of the invention generally relate
to a high-frequency generator with a magnetron and a high-voltage
generator which is connected to the magnetron.
BACKGROUND
[0004] High-voltage generators of the generic type and also
high-frequency generators which have at least one magnetron which
are connected to generic high-voltage generators, are known
extensively in the prior art in principle, so that there is no need
for separate published proof hereof. Generic high-voltage
generators are used to generate high-voltage pulses in order thus
to be able to operate further electrical facilities, such as a
magnetron, for instance. High-voltage generators can be used for
instance to operate a magnetron in its intended way, in order to
provide a high-frequency generator, with which electromagnetic
waves, for instance in the centimeter range or suchlike, can be
generated, so that a wide variety of applications can be realized,
for instance in the area of safety, during a non-destructive
testing of materials and/or suchlike. For this purpose generic
high-voltage generators frequently use a Marx topology, in which a
predetermined number of capacitors is used as an energy storage
unit, wherein the capacitors are charged connected in parallel in a
first operating mode and connected in series in a second operating
mode provide the electrical energy for the high-voltage pulse. The
provided energy is fed to the pulse transformer on a primary
winding. The pulse transformer performs a voltage conversion, so
that the high-voltage pulse is provided accordingly on a secondary
winding of the pulse transformer.
[0005] It is currently desirable in many applications to be able to
consecutively provide a plurality of high-voltage pulses in as
brief a succession as possible. In the meantime it is desirable in
the area of safety and also during the non-destructive testing of
materials to be able to provide pulse rates of the high-voltage
pulses of up to 1 kHz or even more, for instance.
[0006] With high-voltage generators of the generic type, it has
proven to be problematic however that on account of the pulse
transformer after generating a respective individual high-voltage
pulse, the energy stored in the pulse transformer and circuit
possibly connected to its secondary winding has to be absorbed by
way of a freewheel path via the energy storage cells. This has
proven to be disadvantageous in that a time constant for the energy
absorption is in a period of time which can extend beyond one or
more milliseconds. In this way the pulse rate, which can be
provided by the high-voltage generator, is very limited so that in
particular desired pulse rates of up to one kHz or even more cannot
be achieved with known high-voltage generators.
[0007] If the respective energy was namely not absorbed completely
before generating a subsequent high-voltage pulse, this can result
in the stored energy increasing with each pulse. This may lead to
unwanted and hazardous states.
SUMMARY
[0008] At least one embodiment of the invention is directed to
further developing a generic high-voltage generator and a generic
high-frequency generator so that a greater pulse rate can be
achieved.
[0009] At least one embodiment of the invention proposes a
high-voltage generator and a high-frequency generator.
[0010] Advantageous developments result from the features of the
claims.
[0011] At least one embodiment of the invention is directed to a
high-voltage generator for providing a high-voltage pulse,
comprising:
[0012] a plurality of energy storage cells, each energy storage
cell of the plurality of energy storage cells, including
[0013] two input terminals,
[0014] two output terminals and
[0015] one capacitor, the one capacitor being connected with a
first terminal to minus terminals of the two input terminals and
being connected with a second terminal to plus terminals of the two
output terminals,
[0016] wherein a controllable switching element is connected to the
input terminals,
[0017] wherein the plus terminals and the minus terminals are
respectively connected electrically via respective diodes,
respective anodes of the diodes being connected to the input
terminals and respective cathodes of the diodes being connected to
the output terminals;
[0018] a series connection, including the plurality of energy
storage cells, respective input terminals of a respective one of
the plurality of energy storage cells being connected to respective
output terminals of one of the plurality of energy storage cells
arranged relatively upstream in the series connection, the series
connection providing respective input terminals of a relatively
first energy storage cell of the plurality of energy storage cells
as the input terminals and providing respective output terminals of
a relatively last energy storage cell of the plurality of energy
storage cells as the output terminals;
[0019] a pulse transformer including at least one primary winding
and including at least one secondary winding, to provide the
high-voltage pulse, the at least one primary winding being
connected to the plus terminals of the series connection; and
[0020] a charging terminal to charge capacitors of the plurality of
energy storage cells with energy from an energy source, connectable
to the charging terminal, wherein a minus terminal of the charging
terminal is provided by the minus terminal of the output terminal
of the series connection and a plus terminal of the charging
terminal is provided by one of the plus terminals of the relatively
first energy storage cell of the plurality of energy storage
cells,
[0021] wherein at least one respective energy storage cell, of the
plurality of energy storage cells, includes an electrical
resistance, connected in series with the diodes connecting the plus
terminals of the at least one respective energy storage cell
[0022] At least one embodiment of the invention is directed to a
high-frequency generator comprising a magnetron and the
high-voltage generator of at least one embodiment, connected to the
magnetron.
BRIEF DESCRIPTION OF DRAWINGS
[0023] Further advantages and features become apparent from the
following description of example embodiments on the basis of the
appended figures. In the figures the same reference signs denote
the same features and functions.
[0024] In the figures:
[0025] FIG. 1 shows a schematically reduced circuit diagram of a
high-frequency generator, which has a magnetron which is connected
to a high-voltage generator;
[0026] FIG. 2 shows a schematic display of an energy storage cell
of the high-voltage generator according to FIG. 1; and
[0027] FIG. 3 shows a schematic diagram of a high-voltage pulse of
the high-voltage generator, with which the magnetron according to
FIG. 1 is applied.
DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS
[0028] The drawings are to be regarded as being schematic
representations and elements illustrated in the drawings are not
necessarily shown to scale. Rather, the various elements are
represented such that their function and general purpose become
apparent to a person skilled in the art. Any connection or coupling
between functional blocks, devices, components, or other physical
or functional units shown in the drawings or described herein may
also be implemented by an indirect connection or coupling. A
coupling between components may also be established over a wireless
connection. Functional blocks may be implemented in hardware,
firmware, software, or a combination thereof.
[0029] Various example embodiments will now be described more fully
with reference to the accompanying drawings in which only some
example embodiments are shown. Specific structural and functional
details disclosed herein are merely representative for purposes of
describing example embodiments. Example embodiments, however, may
be embodied in various different forms, and should not be construed
as being limited to only the illustrated embodiments. Rather, the
illustrated embodiments are provided as examples so that this
disclosure will be thorough and complete, and will fully convey the
concepts of this disclosure to those skilled in the art.
Accordingly, known processes, elements, and techniques, may not be
described with respect to some example embodiments. Unless
otherwise noted, like reference characters denote like elements
throughout the attached drawings and written description, and thus
descriptions will not be repeated. The present invention, however,
may be embodied in many alternate forms and should not be construed
as limited to only the example embodiments set forth herein.
[0030] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements,
components, regions, layers, and/or sections, these elements,
components, regions, layers, and/or sections, should not be limited
by these terms. These terms are only used to distinguish one
element from another. For example, a first element could be termed
a second element, and, similarly, a second element could be termed
a first element, without departing from the scope of example
embodiments of the present invention. As used herein, the term
"and/or," includes any and all combinations of one or more of the
associated listed items. The phrase "at least one of" has the same
meaning as "and/or"
[0031] Spatially relative terms, such as "beneath," "below,"
"lower," "under," "above," "upper," and the like, may be used
herein for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. It will be understood that the spatially relative
terms are intended to encompass different orientations of the
device in use or operation in addition to the orientation depicted
in the figures. For example, if the device in the figures is turned
over, elements described as "below," "beneath," or "under," other
elements or features would then be oriented "above" the other
elements or features. Thus, the example terms "below" and "under"
may encompass both an orientation of above and below. The device
may be otherwise oriented (rotated 90 degrees or at other
orientations) and the spatially relative descriptors used herein
interpreted accordingly. In addition, when an element is referred
to as being "between" two elements, the element may be the only
element between the two elements, or one or more other intervening
elements may be present.
[0032] Spatial and functional relationships between elements (for
example, between modules) are described using various terms,
including "connected," "engaged," "interfaced," and "coupled."
Unless explicitly described as being "direct," when a relationship
between first and second elements is described in the above
disclosure, that relationship encompasses a direct relationship
where no other intervening elements are present between the first
and second elements, and also an indirect relationship where one or
more intervening elements are present (either spatially or
functionally) between the first and second elements. In contrast,
when an element is referred to as being "directly" connected,
engaged, interfaced, or coupled to another element, there are no
intervening elements present. Other words used to describe the
relationship between elements should be interpreted in a like
fashion (e.g., "between," versus "directly between," "adjacent,"
versus "directly adjacent," etc.).
[0033] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
example embodiments of the invention. As used herein, the singular
forms "a," "an," and "the," are intended to include the plural
forms as well, unless the context clearly indicates otherwise. As
used herein, the terms "and/or" and "at least one of" include any
and all combinations of one or more of the associated listed items.
It will be further understood that the terms "comprises,"
"comprising," "includes," and/or "including," when used herein,
specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. As
used herein, the term "and/or" includes any and all combinations of
one or more of the associated listed items. Expressions such as "at
least one of," when preceding a list of elements, modify the entire
list of elements and do not modify the individual elements of the
list. Also, the term "example" is intended to refer to an example
or illustration.
[0034] When an element is referred to as being "on," "connected
to," "coupled to," or "adjacent to," another element, the element
may be directly on, connected to, coupled to, or adjacent to, the
other element, or one or more other intervening elements may be
present. In contrast, when an element is referred to as being
"directly on," "directly connected to," "directly coupled to," or
"immediately adjacent to," another element there are no intervening
elements present.
[0035] It should also be noted that in some alternative
implementations, the functions/acts noted may occur out of the
order noted in the figures. For example, two figures shown in
succession may in fact be executed substantially concurrently or
may sometimes be executed in the reverse order, depending upon the
functionality/acts involved.
[0036] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, e.g.,
those defined in commonly used dictionaries, should be interpreted
as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an
idealized or overly formal sense unless expressly so defined
herein.
[0037] Before discussing example embodiments in more detail, it is
noted that some example embodiments may be described with reference
to acts and symbolic representations of operations (e.g., in the
form of flow charts, flow diagrams, data flow diagrams, structure
diagrams, block diagrams, etc.) that may be implemented in
conjunction with units and/or devices discussed in more detail
below. Although discussed in a particularly manner, a function or
operation specified in a specific block may be performed
differently from the flow specified in a flowchart, flow diagram,
etc. For example, functions or operations illustrated as being
performed serially in two consecutive blocks may actually be
performed simultaneously, or in some cases be performed in reverse
order. Although the flowcharts describe the operations as
sequential processes, many of the operations may be performed in
parallel, concurrently or simultaneously. In addition, the order of
operations may be re-arranged. The processes may be terminated when
their operations are completed, but may also have additional steps
not included in the figure. The processes may correspond to
methods, functions, procedures, subroutines, subprograms, etc.
[0038] Specific structural and functional details disclosed herein
are merely representative for purposes of describing example
embodiments of the present invention. This invention may, however,
be embodied in many alternate forms and should not be construed as
limited to only the embodiments set forth herein.
[0039] Units and/or devices according to one or more example
embodiments may be implemented using hardware, software, and/or a
combination thereof. For example, hardware devices may be
implemented using processing circuitry such as, but not limited to,
a processor, Central Processing Unit (CPU), a controller, an
arithmetic logic unit (ALU), a digital signal processor, a
microcomputer, a field programmable gate array (FPGA), a
System-on-Chip (SoC), a programmable logic unit, a microprocessor,
or any other device capable of responding to and executing
instructions in a defined manner. Portions of the example
embodiments and corresponding detailed description may be presented
in terms of software, or algorithms and symbolic representations of
operation on data bits within a computer memory. These descriptions
and representations are the ones by which those of ordinary skill
in the art effectively convey the substance of their work to others
of ordinary skill in the art. An algorithm, as the term is used
here, and as it is used generally, is conceived to be a
self-consistent sequence of steps leading to a desired result. The
steps are those requiring physical manipulations of physical
quantities. Usually, though not necessarily, these quantities take
the form of optical, electrical, or magnetic signals capable of
being stored, transferred, combined, compared, and otherwise
manipulated. It has proven convenient at times, principally for
reasons of common usage, to refer to these signals as bits, values,
elements, symbols, characters, terms, numbers, or the like.
[0040] It should be borne in mind, however, that all of these and
similar terms are to be associated with the appropriate physical
quantities and are merely convenient labels applied to these
quantities. Unless specifically stated otherwise, or as is apparent
from the discussion, terms such as "processing" or "computing" or
"calculating" or "determining" of "displaying" or the like, refer
to the action and processes of a computer system, or similar
electronic computing device/hardware, that manipulates and
transforms data represented as physical, electronic quantities
within the computer system's registers and memories into other data
similarly represented as physical quantities within the computer
system memories or registers or other such information storage,
transmission or display devices.
[0041] In this application, including the definitions below, the
term `module` or the term `controller` may be replaced with the
term `circuit.` The term `module` may refer to, be part of, or
include processor hardware (shared, dedicated, or group) that
executes code and memory hardware (shared, dedicated, or group)
that stores code executed by the processor hardware.
[0042] The module may include one or more interface circuits. In
some examples, the interface circuits may include wired or wireless
interfaces that are connected to a local area network (LAN), the
Internet, a wide area network (WAN), or combinations thereof. The
functionality of any given module of the present disclosure may be
distributed among multiple modules that are connected via interface
circuits. For example, multiple modules may allow load balancing.
In a further example, a server (also known as remote, or cloud)
module may accomplish some functionality on behalf of a client
module.
[0043] Software may include a computer program, program code,
instructions, or some combination thereof, for independently or
collectively instructing or configuring a hardware device to
operate as desired. The computer program and/or program code may
include program or computer-readable instructions, software
components, software modules, data files, data structures, and/or
the like, capable of being implemented by one or more hardware
devices, such as one or more of the hardware devices mentioned
above. Examples of program code include both machine code produced
by a compiler and higher level program code that is executed using
an interpreter.
[0044] For example, when a hardware device is a computer processing
device (e.g., a processor, Central Processing Unit (CPU), a
controller, an arithmetic logic unit (ALU), a digital signal
processor, a microcomputer, a microprocessor, etc.), the computer
processing device may be configured to carry out program code by
performing arithmetical, logical, and input/output operations,
according to the program code. Once the program code is loaded into
a computer processing device, the computer processing device may be
programmed to perform the program code, thereby transforming the
computer processing device into a special purpose computer
processing device. In a more specific example, when the program
code is loaded into a processor, the processor becomes programmed
to perform the program code and operations corresponding thereto,
thereby transforming the processor into a special purpose
processor.
[0045] Software and/or data may be embodied permanently or
temporarily in any type of machine, component, physical or virtual
equipment, or computer storage medium or device, capable of
providing instructions or data to, or being interpreted by, a
hardware device. The software also may be distributed over network
coupled computer systems so that the software is stored and
executed in a distributed fashion. In particular, for example,
software and data may be stored by one or more computer readable
recording mediums, including the tangible or non-transitory
computer-readable storage media discussed herein.
[0046] Even further, any of the disclosed methods may be embodied
in the form of a program or software. The program or software may
be stored on a non-transitory computer readable medium and is
adapted to perform any one of the aforementioned methods when run
on a computer device (a device including a processor). Thus, the
non-transitory, tangible computer readable medium, is adapted to
store information and is adapted to interact with a data processing
facility or computer device to execute the program of any of the
above mentioned embodiments and/or to perform the method of any of
the above mentioned embodiments.
[0047] Example embodiments may be described with reference to acts
and symbolic representations of operations (e.g., in the form of
flow charts, flow diagrams, data flow diagrams, structure diagrams,
block diagrams, etc.) that may be implemented in conjunction with
units and/or devices discussed in more detail below. Although
discussed in a particularly manner, a function or operation
specified in a specific block may be performed differently from the
flow specified in a flowchart, flow diagram, etc. For example,
functions or operations illustrated as being performed serially in
two consecutive blocks may actually be performed simultaneously, or
in some cases be performed in reverse order.
[0048] According to one or more example embodiments, computer
processing devices may be described as including various functional
units that perform various operations and/or functions to increase
the clarity of the description. However, computer processing
devices are not intended to be limited to these functional units.
For example, in one or more example embodiments, the various
operations and/or functions of the functional units may be
performed by other ones of the functional units. Further, the
computer processing devices may perform the operations and/or
functions of the various functional units without sub-dividing the
operations and/or functions of the computer processing units into
these various functional units.
[0049] Units and/or devices according to one or more example
embodiments may also include one or more storage devices. The one
or more storage devices may be tangible or non-transitory
computer-readable storage media, such as random access memory
(RAM), read only memory (ROM), a permanent mass storage device
(such as a disk drive), solid state (e.g., NAND flash) device,
and/or any other like data storage mechanism capable of storing and
recording data. The one or more storage devices may be configured
to store computer programs, program code, instructions, or some
combination thereof, for one or more operating systems and/or for
implementing the example embodiments described herein. The computer
programs, program code, instructions, or some combination thereof,
may also be loaded from a separate computer readable storage medium
into the one or more storage devices and/or one or more computer
processing devices using a drive mechanism. Such separate computer
readable storage medium may include a Universal Serial Bus (USB)
flash drive, a memory stick, a Blu-ray/DVD/CD-ROM drive, a memory
card, and/or other like computer readable storage media. The
computer programs, program code, instructions, or some combination
thereof, may be loaded into the one or more storage devices and/or
the one or more computer processing devices from a remote data
storage device via a network interface, rather than via a local
computer readable storage medium. Additionally, the computer
programs, program code, instructions, or some combination thereof,
may be loaded into the one or more storage devices and/or the one
or more processors from a remote computing system that is
configured to transfer and/or distribute the computer programs,
program code, instructions, or some combination thereof, over a
network. The remote computing system may transfer and/or distribute
the computer programs, program code, instructions, or some
combination thereof, via a wired interface, an air interface,
and/or any other like medium.
[0050] The one or more hardware devices, the one or more storage
devices, and/or the computer programs, program code, instructions,
or some combination thereof, may be specially designed and
constructed for the purposes of the example embodiments, or they
may be known devices that are altered and/or modified for the
purposes of example embodiments.
[0051] A hardware device, such as a computer processing device, may
run an operating system (OS) and one or more software applications
that run on the OS. The computer processing device also may access,
store, manipulate, process, and create data in response to
execution of the software. For simplicity, one or more example
embodiments may be exemplified as a computer processing device or
processor; however, one skilled in the art will appreciate that a
hardware device may include multiple processing elements or
processors and multiple types of processing elements or processors.
For example, a hardware device may include multiple processors or a
processor and a controller. In addition, other processing
configurations are possible, such as parallel processors.
[0052] The computer programs include processor-executable
instructions that are stored on at least one non-transitory
computer-readable medium (memory). The computer programs may also
include or rely on stored data. The computer programs may encompass
a basic input/output system (BIOS) that interacts with hardware of
the special purpose computer, device drivers that interact with
particular devices of the special purpose computer, one or more
operating systems, user applications, background services,
background applications, etc. As such, the one or more processors
may be configured to execute the processor executable
instructions.
[0053] The computer programs may include: (i) descriptive text to
be parsed, such as HTML (hypertext markup language) or XML
(extensible markup language), (ii) assembly code, (iii) object code
generated from source code by a compiler, (iv) source code for
execution by an interpreter, (v) source code for compilation and
execution by a just-in-time compiler, etc. As examples only, source
code may be written using syntax from languages including C, C++, C
#, Objective-C, Haskell, Go, SQL, R, Lisp, Java.RTM., Fortran,
Perl, Pascal, Curl, OCaml, Javascript.RTM., HTML5, Ada, ASP (active
server pages), PHP, Scala, Eiffel, Smalltalk, Erlang, Ruby,
Flash.RTM., Visual Basic.RTM., Lua, and Python.RTM..
[0054] Further, at least one embodiment of the invention relates to
the non-transitory computer-readable storage medium including
electronically readable control information (procesor executable
instructions) stored thereon, configured in such that when the
storage medium is used in a controller of a device, at least one
embodiment of the method may be carried out.
[0055] The computer readable medium or storage medium may be a
built-in medium installed inside a computer device main body or a
removable medium arranged so that it can be separated from the
computer device main body. The term computer-readable medium, as
used herein, does not encompass transitory electrical or
electromagnetic signals propagating through a medium (such as on a
carrier wave); the term computer-readable medium is therefore
considered tangible and non-transitory. Non-limiting examples of
the non-transitory computer-readable medium include, but are not
limited to, rewriteable non-volatile memory devices (including, for
example flash memory devices, erasable programmable read-only
memory devices, or a mask read-only memory devices); volatile
memory devices (including, for example static random access memory
devices or a dynamic random access memory devices); magnetic
storage media (including, for example an analog or digital magnetic
tape or a hard disk drive); and optical storage media (including,
for example a CD, a DVD, or a Blu-ray Disc). Examples of the media
with a built-in rewriteable non-volatile memory, include but are
not limited to memory cards; and media with a built-in ROM,
including but not limited to ROM cassettes; etc. Furthermore,
various information regarding stored images, for example, property
information, may be stored in any other form, or it may be provided
in other ways.
[0056] The term code, as used above, may include software,
firmware, and/or microcode, and may refer to programs, routines,
functions, classes, data structures, and/or objects. Shared
processor hardware encompasses a single microprocessor that
executes some or all code from multiple modules. Group processor
hardware encompasses a microprocessor that, in combination with
additional microprocessors, executes some or all code from one or
more modules. References to multiple microprocessors encompass
multiple microprocessors on discrete dies, multiple microprocessors
on a single die, multiple cores of a single microprocessor,
multiple threads of a single microprocessor, or a combination of
the above.
[0057] Shared memory hardware encompasses a single memory device
that stores some or all code from multiple modules. Group memory
hardware encompasses a memory device that, in combination with
other memory devices, stores some or all code from one or more
modules.
[0058] The term memory hardware is a subset of the term
computer-readable medium. The term computer-readable medium, as
used herein, does not encompass transitory electrical or
electromagnetic signals propagating through a medium (such as on a
carrier wave); the term computer-readable medium is therefore
considered tangible and non-transitory. Non-limiting examples of
the non-transitory computer-readable medium include, but are not
limited to, rewriteable non-volatile memory devices (including, for
example flash memory devices, erasable programmable read-only
memory devices, or a mask read-only memory devices); volatile
memory devices (including, for example static random access memory
devices or a dynamic random access memory devices); magnetic
storage media (including, for example an analog or digital magnetic
tape or a hard disk drive); and optical storage media (including,
for example a CD, a DVD, or a Blu-ray Disc). Examples of the media
with a built-in rewriteable non-volatile memory, include but are
not limited to memory cards; and media with a built-in ROM,
including but not limited to ROM cassettes; etc. Furthermore,
various information regarding stored images, for example, property
information, may be stored in any other form, or it may be provided
in other ways.
[0059] The apparatuses and methods described in this application
may be partially or fully implemented by a special purpose computer
created by configuring a general purpose computer to execute one or
more particular functions embodied in computer programs. The
functional blocks and flowchart elements described above serve as
software specifications, which can be translated into the computer
programs by the routine work of a skilled technician or
programmer.
[0060] Although described with reference to specific examples and
drawings, modifications, additions and substitutions of example
embodiments may be variously made according to the description by
those of ordinary skill in the art. For example, the described
techniques may be performed in an order different with that of the
methods described, and/or components such as the described system,
architecture, devices, circuit, and the like, may be connected or
combined to be different from the above-described methods, or
results may be appropriately achieved by other components or
equivalents.
[0061] With respect to a generic high-voltage generator, it is in
particular proposed in at least one embodiment that at least one of
the energy storage cells has an electrical resistance which is
connected in series with the diode connecting the plus terminals of
this energy storage cell.
[0062] With respect to a generic high-frequency generator, it is
proposed in at least one embodiment that its high-voltage generator
is embodied according to at least one embodiment of the
invention.
[0063] At least one embodiment of the invention is based on a
principle that it is possible to achieve an increased damping with
respect to the energy absorption via the electrical resistance so
that the time for the adsorption of energy can be significantly
reduced. In this regard it has emerged that the electrical
resistance should not be arranged at any position in the
series-connected energy storage cells, because the functionality
with respect to the provision of the high-voltage pulse and/or also
with respect to the charging of the capacitors could then be
impaired. In order to avoid this as far as possible, the electrical
resistance according to the invention is connected in series with
the diode connecting the plus terminals of the first energy storage
cell. This means that the impairment of the intended function of
the high-voltage generator can largely be kept to a minimum.
[0064] At least one embodiment of the invention therefore allows a
repetition rate of the high-voltage pulse or a pulse rate to
increase significantly so that it is possible in particular to
achieve a pulse frequency of 1 kHz or even greater.
[0065] At least one embodiment of the invention can moreover be
easily realized by only a supplement needing to be performed on one
of the energy storage cells. Provision can be made in this way, for
instance, for only the first of the energy storage cells of the
series connection of an already existing high-voltage generator
needing to be replaced with an energy storage cell embodied in
accordance with the invention, for instance. Therefore already
existing high-voltage generators can be easily retrofitted.
[0066] Overall, the time constant for the absorption and thus that
of a freewheel current can be significantly reduced by the series
connection, because the time constant is at least indirectly
proportional to an overall resistance of the corresponding
freewheel path through the energy storage cells of the series
connection.
[0067] One important aspect of at least one embodiment of the
invention is therefore to absorb the stored energy downstream of a
pulse end of the high-voltage pulse with as small a time constant
as possible, via a targeted arrangement of at least one electrical
resistance in the freewheel path, wherein at the same time
impairing the provision of the high-voltage pulse is essentially to
be avoided. This then allows a pulse rate to significantly
increase.
[0068] In normal operation, high-voltage pulses can be provided via
the high-voltage generator, with which a pulse power of for
instance approx. 8 kW to approx. 10 Kw can be achieved. Naturally
smaller or larger powers can also be realized depending on use. A
high-voltage pulse can comprise a pulse voltage with an amplitude
in a range of approx. 10 KV to approx. 50 KV, for instance.
Depending on the use, the voltage can however also vary and in
particular also be greater than 50 KV, for instance.
[0069] The high-voltage pulses are provided by way of the secondary
winding of the pulse transformer. For this purpose, the primary
winding of the pulse transformer is applied accordingly via the
energy storage cells connected in series, so that the desired
high-voltage pulse can be provided on the secondary side. For this
purpose, provision can be made for energy pulses which can comprise
an amplitude of for instance approx. 500 Volts up to approx. 2 KV
or even more to be provided via series-connected energy storage
cells.
[0070] Provision can be made here for this voltage to be able to be
set by, for instance, only as many of the energy storage cells
being activated for the provision of a respective high-voltage
pulse as is required for a respective desired high-voltage pulse.
Therefore not all energy storage cells in the series connection
naturally need to be activated for the provision of a respective
high-voltage pulse. Depending on requirements, this can also vary
or even be changed during an individual high-voltage pulse. It is
therefore possible, for instance, in order to achieve as large a
pulse width as possible, to switch on or activate additional energy
storage cells during the time frame of the high-voltage pulse with
increasing time, in order to stabilize an amplitude of the
high-voltage pulse for instance or suchlike. By activating or
deactivating individual energy storage cells in the series
connection, it is therefore possible to have an effect on the
high-voltage pulse with respect to its properties in a desired
manner.
[0071] The energy storage cells can be embodied as individually
manageable components so that it is possible to achieve high
flexibility with respect to creating the series connection. By only
the input terminals of a respective one of the energy storage cells
being electrically connected to the output terminals of an
immediately preceding energy storage cell in the series connection,
the series connection can therefore be retrofitted almost
arbitrarily with respect to the number of energy storage cells. As
a result, a modular structure can be achieved which allows the
high-voltage generator to be adjusted to a desired application with
significant flexibility.
[0072] Here the capacitors of the energy storage cells are
preferably selected with respect to their voltage strength,
capacitance, and current carrying capacity so that the desired
high-voltage pulse can be realized with respect to its energy
content.
[0073] In order to activate a respective one of the energy storage
cells in the series connection while providing the high-voltage
pulse, the controllable switching element which is switched into a
switched-on switching state in order to activate the energy storage
cell is provided for each of the energy storage cells. If no
high-voltage pulse is provided or the corresponding energy storage
cell is deactivated or its capacitor charged, the switching element
is in a switched-off switching state.
[0074] The two diodes are provided in order to realize the
functionality of a respective energy storage cell. Although in the
present embodiment diodes are provided, the diodes can if necessary
also naturally be replaced by switching elements, in particular
semiconductor switching elements, which are operated suitably in a
switching operation. In one such case the diodes can therefore be
embodied like the controllable switching element, for instance. The
switching elements are then to be controlled in a predeterminable
manner via a suitable control unit, so that the desired
functionality can be provided, which comprises at least the
functionality of the diodes.
[0075] The pulse transformer is designed in order to be able to
transmit energy pulses with a high slew rate. For this purpose, the
pulse transformer can have a suitable ferromagnetic core, which can
be formed from a suitable ferrite or suchlike for instance. The at
least one primary winding and the at least one secondary winding
can be wound in a suitable manner onto the core of the pulse
transformer, by the windings being arranged one above the other,
for instance. Particularly advantageously, the windings can also be
wound at least partially bifilar. For this reason, the pulse
transformer can however also have two or more primary and/or
secondary windings. These can be connected at least partially in
parallel.
[0076] The high-voltage generator further has the charging terminal
for charging the capacitors with energy from an energy source which
can be connected to the charging terminal. The charging terminal
can be provided to be connected to a direct voltage energy source
which provides a predetermined direct voltage. For instance,
provision can be made for the energy source to provide a direct
voltage in a range of approx. 0 V up to approx. 400 V. The energy
source can to this end comprise a power supply unit, which can be
connected to a public power supply network as an energy source or
suchlike. The public power supply network can provide a three-phase
alternating voltage, for instance, which can amount to approx. 400
V, for instance. A frequency of the alternating voltage can lie for
instance in a range of approx. 50 Hz to approx. 60 Hz.
[0077] A minus terminal of the charging terminal is provided here
by the minus terminal of the output terminal of the series
connection and a plus terminal of the charging terminal is provided
by one of the plus terminals of the first of the energy storage
cells. This makes it possible to supply the energy storage cells
with electrical energy in parallel from the energy source so that
their capacitors are charged. The switching topology of the series
connection and the energy storage cells causes the capacitors, for
charging in the manner of a parallel connection, to be electrically
coupled with the energy source so that they are simultaneously
charged by the energy source, namely to a capacitor voltage which
essentially corresponds approximately to the direct voltage
provided by the energy source. This achieves a rapid charging of
the capacitors of the energy storage cells, so that a
correspondingly large pulse rate of the high-voltage generator can
also be reached.
[0078] The energy source can also be formed by an alternating
voltage source, however. In this case provision can then be made
for the charging terminal to be formed by the plus terminal of the
input terminals of the first of the energy storage cells of the
series connection and the minus terminal of the output terminals of
the series connection. In this case, the diodes can at the same
time also realize a rectifier function, so that a charging unit
connected to the energy supply network can be reduced or even
spared.
[0079] The electrical resistance can, depending on requirements and
possibly also resistance value, also be realized by a cable guide
of the corresponding energy storage cell. The electrical resistance
can naturally also be formed by a separate component, which is
arranged on the respective energy storage cell.
[0080] The electrical resistance is preferably embodied to be able
to provide a suitable capability so that the energy to be absorbed
can be reliably and safely converted into heat in the provided
time. For this purpose, provision can furthermore be made for the
electrical resistance to be connected to a suitable cooling unit or
heat sink, which allows thermal energy occurring during normal
operation to be reliably discharged.
[0081] Although the high-frequency generator here has the feature
of the at least one magnetron, this term should however not be
designed restricted hereto. Instead, this term is to be designed so
that a klystron or suchlike can also be provided instead of the
magnetron. In this respect, the term "magnetron" in this disclosure
should also comprise comparable facilities such as the klystron or
suchlike, namely in particular also such facilities which use high
voltage in order to output electromagnetic waves, particularly in
the high-frequency range.
[0082] At least one embodiment of the invention makes it possible
overall for the energy to be absorbed to be able to be absorbed
with a time constant which is significantly smaller than a
millisecond, preferably in the range of a few microseconds. As a
result, a high pulse rate can be achieved for the high-voltage
pulses via the high-voltage generator of at least one embodiment,
so that pulse rates of approx. 1 kHz or even more can also be
achieved.
[0083] As a result, at least one embodiment of the invention also
opens up new application fields so that for instance a container
screening can be carried out at great speed, so that for instance a
container train can already be reliably screened during propulsion
when passing through a corresponding screening system. Furthermore,
another series of further applications naturally result, which can
firstly only be usefully realized because a high pulse rate can be
provided by the high-voltage generator.
[0084] It has proven particularly advantageous if only the first of
the energy storage cells has the electrical resistance. As a
result, at least one embodiment of the invention can be realized
very easily so that only the first of the energy storage cells
needs to be adjusted accordingly. Especially with respect to a
retrofitting of existing high-voltage generators, the invention can
also be easily subsequently realized without any great expense.
Apart from the electrical resistance no further elements are
necessary in principle in order to realize at least one embodiment
of the invention. In this case the invention can be realized
particularly easily, as a result of which there is in particular
the option of easily being able to retrofit the invention in the
case of existing high-voltage generators.
[0085] It is further proposed that a resistance switching element
is connected in parallel with the electrical resistance. This
embodiment is suited in particular to the resistance element not
only exclusively being arranged in the first of the energy storage
cells of the series connection. In principle, the electrical
resistance can naturally also be arranged in another or a number of
arbitrary energy storage cells. A number of electrical resistances
which are arranged in a number of the energy storage cells can
naturally also be provided as an electrical resistance. Since the
electrical resistances arranged in the other energy storage cells
than the first of the energy storage cells can however have an
influence on the provision of the high-voltage pulse and/or further
functions, in this case it is possible for the parallel-connected
resistance switching element to short-circuit the electrical
resistance for the provision of the high-voltage pulse and/or the
further functions so that its influence on the provision of the
high-voltage pulse can essentially be ignored. The electrical
resistance namely only needs to be activated for the period of time
of absorbing the energy.
[0086] The plus terminal of the charging terminal is preferably
provided by the plus terminal of the output terminal of the first
of the energy storage cells. As a result, the capacitor of the
first of the energy storage cells can be directly coupled with the
energy source, which in this case should be a direct voltage
source. As a result, if the first of the energy storage cells has
the electrical resistance, it is also possible for this not to be
automatically activated for the process of charging the capacitors.
Furthermore, in this way it is also possible for the electrical
resistance also not to be automatically activated when the pulse is
provided.
[0087] If, by contrast, the electrical resistance is arranged in
one or more of the energy storage cells, the electrical resistance
should be short-circuited by the resistance switching element for
the process of charging the capacitors in order not only to be able
to carry out the charging process of the capacitors as efficiently
as possible but also as quickly as possible. A large pulse rate for
the high-voltage pulse can further be improved in this way.
[0088] It is also proposed that the electrical resistance has a
resistance value which is dependent on an impedance of the pulse
transformer and/or a capacitance of a circuit connected to the at
least one secondary winding. The resistance value of the electrical
resistance is therefore preferably selected depending on which
impedance the pulse transformer can provide and/or on which
capacitance the circuit connected to the pulse transformer on the
secondary side has. It has been shown, for instance, that with a
momentary break in current on the secondary side of the pulse
transformer, line capacitances in particular of the circuit, but
also possibly further capacitances may result in the energy stored
here being fed via the pulse transformer from the secondary side to
the primary side. This energy can then no longer be fed back into
the capacitors. This energy is therefore to be absorbed on the
primary side with respect to the pulse transformer. The absorption
can be optimized by suitably selecting the resistance value.
[0089] It has further proven particularly advantageous if the
electrical resistance is embodied to be adjustable with respect to
its resistance value. This allows the high-voltage generator to be
easily adjusted to different applications. As a result, the
flexibility with respect to the use of the high-voltage generator
can be further improved.
[0090] According to one development, it is proposed that the
electrical resistance has a resistance value in a range of approx.
0.5.OMEGA. to approx. 15.OMEGA., preferably approx. 5.OMEGA.. A
resistance value has proven to be particularly suitable in this
range for the normal operation of generic high-voltage generators.
It is possible to achieve a rapid absorption of the energy by the
electrical resistance using the resistance values mentioned
above.
[0091] Furthermore, it is proposed that the electrical resistance
is embodied for an electrical power in a range of approx. 0.2 kW to
approx. 10 kW, preferably approx. 1 Kw. Resistances of this type
have proven to be favorable in terms of acquisition and can be
easily arranged in the high-voltage generator. Furthermore, this
power range has proven to be preferable for the use of generic
high-voltage generators in order to be able to achieve the desired
absorption of energy.
[0092] It is also proposed that the electrical resistance is
arranged so as to be replaceable. This ensures that the
high-voltage generator can be easily adjusted to different
operating conditions. Furthermore, there is naturally also the
option of easily replacing a faulty electrical resistance with a
functional electrical resistance. In particular, the maintenance
and reliability can be improved as a result.
[0093] Furthermore, it is proposed that the electrical resistance
is embodied at least partially as a sheet resistance. This means
that the electrical resistance can be applied with electrical
voltage and/or electrical current in a highly dynamic manner. In
particular, it is possible to prevent the electrical resistance
from reaching an unwanted interaction with the pulse transformer
and/or further circuit parts of the high-voltage generator.
Furthermore, it is possible for the energy absorption of the
electrical resistance to be homogenized, so that as uniform a load
of the electrical resistance as possible can be achieved.
[0094] The advantages and effects specified for the inventive
high-voltage generator naturally also apply at the same time to the
high-frequency generator equipped with the inventive high-voltage
generator.
[0095] FIG. 1 shows a schematic, reduced circuit diagram of a
high-frequency generator 10, which comprises a magnetron 48, which
is connected to a high-voltage generator 12 by way of lines 50. The
high-voltage generator 12 is supplied for its part with electrical
energy from a charging unit 42, which, for this purpose, is
connected for its part to a public power supply network (not shown
further) and is supplied with electrical energy hereby. Here the
charging unit 42 is embodied to be applied with a three-phase
alternating voltage of approx. 400 V via the public energy supply
network. The charging unit 42 is further embodied to provide a
power of approx. 10 kW. The charging unit 42 provides a direct
charging voltage of approx. 400 V. The magnetron 48 and the
electrical lines 50 form a circuit 46.
[0096] The high-voltage generator 12 provides a high-voltage pulse
14 (FIG. 3), with which the magnetron 48 is applied, whereupon the
magnetron 48 outputs a corresponding electromagnetic pulse in the
high-frequency range. The function of the magnetron 48 is known
extensively in the prior art, so that further explanations hereof
are omitted.
[0097] In the present embodiment the high-voltage generator 12
provides a high-voltage pulse 14 with a voltage amplitude here of
approx. 50 KV. Depending on the use and construction of the
magnetron 48, another voltage amplitude can however also be
provided here, for instance 20 KV, 40 KV or even also a voltage
amplitude which is greater than 50 KV.
[0098] In the present embodiment, the magnetron 48 has the property
that a current flow through the lines 40 ends abruptly when a
voltage of approx. 30 KV is not met. This produces problems with
respect to the remaining energy of the high-voltage pulse 14, which
is stored at least partially also capacitively in the lines 50.
This energy cannot be used again in the high-voltage generator 12
for storage purposes, as explained in more detail below.
[0099] FIG. 1 also shows the schematic design of the high-voltage
generator 12, which provides the high-voltage pulse 14 for
operating the magnetron 48. The high-voltage generator 12 is
therefore used to provide a plurality of high-voltage pulses 14
which follow one another in terms of time.
[0100] For this purpose, the high-voltage generator 12 has a
plurality of energy storage cells 16, 18, of which one individual
(16) is shown in a schematic circuit diagram in FIG. 2. Each of the
energy storage cells 16, 18 has in each case two input and two
output terminals 20, 22, 24, 26 and a capacitor 28. The capacitor
28 is connected with a first of its terminals to a minus terminal
22 of the two input terminals and with a second of its terminals to
a plus terminal 24 of the two output terminals of the respective
one of the energy storage cells 16, 18. A controllable switching
element 30 is connected between the input terminals 20, 22 of a
respective one of the energy storage cells 16, 18. The switching
element 30 can be formed by a semiconductor switching element, for
instance a thyristor, a transistor operated in a switching mode, in
particular an insulated gate bipolar transistor (IGBT) but also a
field effect transistor, for instance a metal oxide semiconductor
field effect transistor (MOSFET) or suchlike.
[0101] The plus terminals 20, 24 and correspondingly also the minus
terminals 22, 26 are in each case electrically connected to one
another by way of a respective diode 32, 34, by respective anodes
of the diodes 32, 34 being connected to the input terminals 20, 22
and respective cathodes of the diodes 32, 34 being connected to the
output terminals 24, 26.
[0102] In the embodiment according to FIG. 1 shown here, the
high-voltage generator 12 comprises five energy storage cells 16,
18, which are connected to one another here in the series
connection. In the series connection, the respective input
terminals 22, 22 of a respective one of the energy storage cells
16, 18 are connected to the respective output terminals 24, 26 of
one of the energy storage cells 16, 18 arranged immediately
upstream in the series connection so that the series connection
provides as input terminals the input terminals 20, 22 of the first
of the energy storage cells 18 and as output terminals the output
terminals 24, 26 of the last of the energy storage cells 16. In
alternative embodiments, the number of energy storage cells 16 can
naturally be varied almost arbitrarily in order to adjust the
high-voltage generator 12 to a respective application. This is not
decisive for the use of the invention, however.
[0103] The high-frequency generator 12 further comprises a pulse
transformer 36, which here has a primary winding 38 and a secondary
winding 40 for providing the high-voltage pulse 14. The circuit 46
is connected to the secondary winding 40. The primary winding 38
and the secondary winding 40 are wound onto a ferromagnetic core,
not shown further. Provision is also made here for the primary
winding 38 and the secondary winding 40 to be wound bifilar onto
the core. The primary winding 38 is further connected to the plus
terminals 20, 24 in the series connection.
[0104] The high-voltage generator 12 further comprises a charging
terminal, not shown, for charging the capacitors 28 with energy
from the charging unit 42 which can be connected to the charging
terminal. This is only shown schematically in the present
embodiment. In this embodiment, the charging unit 42 is not
included in the high-voltage generator 12, but can, however, in
alternative embodiments, also be included in the high-voltage
generator 12. A minus terminal of the charging terminal is provided
here by the minus terminal 26 of the output terminal of the series
connection and a plus terminal of the charging terminal is provided
here by the plus terminal 24 of the output terminal of the first of
the energy storage cells 18.
[0105] During normal operation the high-voltage generator 12
functions in principle according to the Marx principle as
follows:
[0106] In a first operating mode, in which the capacitors 28 are
charged, the controllable switching elements 30 are in the
switched-off switching state. The charging unit 42 provides the
charging voltage of approx. 400 V as a direct voltage by way of the
plus terminal 24 of the first energy storage cell 18 and the minus
terminal 26 of the last of the energy storage cells 16, which
provide the charging terminals, as a result of which the capacitors
28 are charged to a corresponding direct voltage. In this way the
charge current flow takes place by way of the plus terminal 24 of
the first energy storage cell 18 directly to its capacitor 28 and
via the diodes 32 to the capacitors 28 of the further of the energy
storage cells 16. The current flow finishes across the diodes 34 of
the energy storage cells 16, 18.
[0107] In a second operating mode, in which the high-voltage pulse
14 is provided by the high-voltage generator 12, a corresponding
number of energy storage cells 16, 18 is activated according to the
desired voltage amplitude of the high-voltage pulse 14, by its
controllable switching elements 30 being switched into the
switched-on switching state. As a result, a direct voltage
determined by the capacitors 28 connected in series in this way is
available on the primary winding 38 and is transformed via the
pulse transformer 36 to the desired high voltage so that the
corresponding high-voltage pulse 14 is available on the secondary
winding 40.
[0108] A current converter, not shown in further detail, can be
used to capture the current in the lines 50 of the switching
circuit 46. If the current drops abruptly, this can be detected and
the switching elements 30 of the energy storage cells 16, 18 are
switched into the switched-off switching state. In this switching
state, the energy remaining in the switching circuit 46 can then be
absorbed by way of the primary winding 38 and the diodes 32.
[0109] This means:
[0110] if an abrupt end to the current flow now occurs in the
switching circuit 46, as explained above, it is necessary for the
energy still available at this point in time in the switching
circuit 46 to be discharged. To this end, the stored energy is fed
via the pulse transformer 36 and its primary winding 38 back to the
series connection comprising the energy storage cells 16, 18,
wherein a current flow is established through the diodes 32 of the
energy storage cells 16, 18. The energy storage cells 16, 18
therefore make available a freewheel path.
[0111] At this point in time, the controllable switching elements
30 are in the switched-off switching state. On account of the
minimal damping in this current circuit or freewheel path, a decay
time constant for the absorption of the energy is comparatively
large and typically amounts to approx. 1 ms to 2 ms. This fact is
explained further on the basis of FIG. 3.
[0112] FIG. 3 shows a schematic diagram of an energy-time diagram,
which is only used for a high-quality display and is not true to
scale. Here the energy is dependent on a squared primary current of
the primary winding 38. A horizontal axis is assigned to the time
t, whereas a vertical axis is assigned to the energy J. The current
flow in the switching circuit 46 ends at a time instant t1. With a
graph 52, the absorption behavior here is shown in the
afore-described case without an electrical resistance 44. At a time
instant t3 the energy is largely absorbed so that a new
high-voltage pulse 14 can be provided. The time constant amounts
here to approx. 1 ms.
[0113] With the afore-cited time constant, it is not possible to be
able to provide high-voltage pulses 14 with a repetition rate or
pulse rate in a region of 1 kHz or more. If, in this embodiment,
the pulse rate were namely to move in the corresponding order of
magnitude, energy would accumulate increasingly in the system. This
may result in dangerous states and incidentally also cause
damage.
[0114] In order now to reduce the afore-cited problem and to be
able to increase the pulse rate for the high-voltage pulse 14, it
is proposed in accordance with the invention that the first of the
energy storage cells 18 has an electrical resistance 44 which is
connected in series with the diode 32 connecting the plus terminals
20, 24 of this energy storage cell 18. From a purely
electrotechnical viewpoint, the sequence of series connection of
these two elements is irrelevant here.
[0115] The electrical resistance 44, which here has a resistance
value of approx. 5.OMEGA. and is designed for an electric power of
approx. 1 kW, allows the time constant for the energy absorption to
be significantly shortened, as apparent from FIG. 3 on the basis of
the graph 54. At time instant t2, which is clearly before time
instant t3, the energy is already sufficiently absorbed.
[0116] Decay times in a region of significantly less than approx. 1
.mu.s can be achieved in this way, for instance approx. 100 ns or
suchlike. Conversely a decay time in the region of approx. 1 ms or
even 2 ms is realized without the electrical resistance 44. The
decay times in the diagram in FIG. 3 correspond to respective
differences in the time instants t3-t1 or t2-t1.
[0117] By way of the now achievable, very short decay time, the
pulse rate for the high-voltage pulses 14 can be significantly
increased so that pulse rates in the region of approx. 1 kHz or
even more can also be achieved.
[0118] Even if the present embodiment of the high-voltage generator
12 provides that generally the plus terminal 24 has a positive
electrical potential during normal operation compared with the plus
terminal 20, the high-voltage generator 12 and its series
connection and the energy storage cells can also be designed so
that a corresponding negative potential is present. A corresponding
dual circuit arrangement can be easily realized accordingly by the
person skilled in the art. The use of the invention remains
unaffected hereby, however.
[0119] Furthermore, the electric resistance 44 can naturally also
be provided in other of the energy storage cells 16. It can also be
provided in several of the energy storage cells 16. In one such
case, it is desirable however for the electrical resistance 44 then
to be short-circuited via a resistance switching element so that no
unnecessary losses occur in the high-voltage pulse generation of
the high-voltage pulse 14. Furthermore, it is also useful to
short-circuit the electrical resistance in this regard during a
charging process for charging the capacitors 28, in order to be
able to achieve as rapid a charging of the capacitors 28 as
possible.
[0120] Embodiments of the invention are naturally not restricted to
precisely five energy storage cells being used. The high-voltage
generator can naturally comprise an almost arbitrary number of
energy storage cells, which are connected in series in the said
manner. The number of energy storage cells can in particular be
selected as a function of a value of the voltage of the charging
unit and/or an amplitude of the high-voltage pulse to be
provided.
[0121] Overall the example embodiments are only used to explain the
invention and should not be restricted.
[0122] Although the present invention has been disclosed in the
form of preferred embodiments and variations thereon, it will be
understood that numerous additional modifications and variations
could be made thereto without departing from the scope of the
invention. For the sake of clarity, it is to be understood that the
use of "a" or "an" throughout this application does not exclude a
plurality, and "comprising" does not exclude other steps or
elements. The mention of a "unit" or a "device" does not preclude
the use of more than one unit or device.
[0123] The patent claims of the application are formulation
proposals without prejudice for obtaining more extensive patent
protection. The applicant reserves the right to claim even further
combinations of features previously disclosed only in the
description and/or drawings.
[0124] References back that are used in dependent claims indicate
the further embodiment of the subject matter of the main claim by
way of the features of the respective dependent claim; they should
not be understood as dispensing with obtaining independent
protection of the subject matter for the combinations of features
in the referred-back dependent claims. Furthermore, with regard to
interpreting the claims, where a feature is concretized in more
specific detail in a subordinate claim, it should be assumed that
such a restriction is not present in the respective preceding
claims.
[0125] Since the subject matter of the dependent claims in relation
to the prior art on the priority date may form separate and
independent inventions, the applicant reserves the right to make
them the subject matter of independent claims or divisional
declarations. They may furthermore also contain independent
inventions which have a configuration that is independent of the
subject matters of the preceding dependent claims.
[0126] None of the elements recited in the claims are intended to
be a means-plus-function element within the meaning of 35 U.S.C.
.sctn. 112(f) unless an element is expressly recited using the
phrase "means for" or, in the case of a method claim, using the
phrases "operation for" or "step for."
[0127] Example embodiments being thus described, it will be obvious
that the same may be varied in many ways. Such variations are not
to be regarded as a departure from the spirit and scope of the
present invention, and all such modifications as would be obvious
to one skilled in the art are intended to be included within the
scope of the following claims.
* * * * *